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BIOLOGY HANDOUTTOPIC: ANIMAL NUTRITION
Teacher in Charge: ARIF ULLAH 1
EDEXCEL SYLLABUS (Section 2 - E)2.24 understand that a balanced
diet should include appropriate proportions ofcarbohydrate,
protein, lipid, vitamins, minerals, water and dietary fibre2.25
identify the sources and describe the functions of carbohydrate,
protein, lipid(fats and oils), vitamins A, C and D, the mineral
ions calcium and iron, water anddietary fibre as components of the
diet2.26 understand how energy requirements vary with activity
levels, age andpregnancy2.27 describe the structure and function of
the human alimentary canal, includingthe mouth, oesophagus,
stomach, small intestine (duodenum and ileum), largeintestine
(colon and rectum) and pancreas2.28 understand how food is moved
through the gut by peristalsis2.29 understand the role of digestive
enzymes, including the digestion of starch toglucose by amylase and
maltase, the digestion of proteins to amino acids byproteases and
the digestion of lipids to fatty acids and glycerol by lipases2.30
understand that bile is produced by the liver and stored in the
gall bladder2.31 understand the role of bile in neutralising
stomach acid and emulsifying lipids2.32 understand how the small
intestine is adapted for absorption, including thestructure of a
villus2.33B practical: investigate the energy content in a food
sample
(HUMAN BIOLOGY HAS TEETH AND FOOD PRESERVATION)
CAMBRIDGE SYLLABUS (5)(a) list the chemical elements that make
up:
• carbohydrates;• fats;• proteins;
(b) describe tests for:• starch (Iodine in Potassium Iodide
solution);• reducing sugars (Benedict’s solution);• protein (Biuret
test);• fats (Ethanol emulsion test);
(c) list the principal sources of, and describe the dietary
importance ofcarbohydrates, fats, proteins, vitamins (C and D
only), mineral salts (calcium andiron only), fibre (roughage) and
water;(d) name the diseases and describe the symptoms resulting
from deficiencies ofvitamin C (scurvy), vitamin D (rickets),
mineral salts calcium (rickets) and iron(anaemia);(e) understand
the concept of a balanced diet;(f) explain why diet, especially
energy intake, should be related to age, sex andactivity of an
individual;(g) state the effects of malnutrition in relation to
starvation, heart disease,constipation and obesity;
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BIOLOGY HANDOUTTOPIC: ANIMAL NUTRITION
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(h) discuss the problems that contribute to famine (unequal
distribution of food,drought and flooding, increasing
population);(i) identify the main regions of the alimentary canal
and the associated organs:mouth (buccal) cavity, salivary glands,
oesophagus, stomach, duodenum,pancreas, gall bladder, liver, ileum,
colon, rectum and anus;(j) describe the main functions of these
parts in relation to ingestion, digestion,absorption, assimilation
and egestion of food, as appropriate;(k) identify the different
types of human teeth and describe their structure andfunctions;(l)
state the causes of dental decay and describe the proper care of
teeth;(m) describe peristalsis;(n) explain why most foods must be
digested;(o) describe:
• digestion in the alimentary canal;• the functions of a typical
amylase, protease and lipase, listing the substrates
and end-products;(p) describe the structure of a villus,
including the roles of capillaries and lacteals;(q) describe the
significance of villi in increasing the internal surface area;
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BIOLOGY HANDOUTTOPIC: ANIMAL NUTRITION
Teacher in Charge: ARIF ULLAH 3
Living organisms require food to provide them energy for the
vital activities of thebody, to maintain themselves and for
movement and growth. Green plants canmake use of the energy from
the sun through the process of photosynthesis butother organisms
need food to supply their energy needs. Thus the food thatorganisms
feed on contains a store of energy. This stored energy is
calledpotential chemical energy.
This potential energy present in the food is converted into
kinetic energy in ourcells which helps us to move our skeletons and
contract our muscles. Howeversome of the energy is also lost as
heat energy.
NUTRIENTS IN FOODNutrients are chemical substances found in the
body which nourish the body. Thenutrients may be classified into
two major groups.
Organic nutrients:They are the nutrients which are obtained from
living organisms. They arecompounds of carbon. Examples include:
carbohydrates, fats, proteins, vitaminsand dietary fibre.
Inorganic nutrients:Inorganic nutrients include water and all
the mineral salts.
a) CARBOHYDRATES
Carbohydrates are organic compounds made up of the elements
carbon, hydrogenand oxygen. The hydrogen and oxygen atoms are
present in the same ratio as inwater, i.e. 2 : 1.
The generalized formula for carbohydrates is CnH2mOm.
In case of sucrose (C12H22O11), n= 12, and m is equal to
eleven.Therefore hydrogen, which is equal to 2m equals 2(11)=
22.Carbohydrates include sugars, starch, the cellulose of plant
cell walls and anumber of related substances.
FUNCTIONS OF CARBOHYDRATES:Carbohydrates are needed
As a source of energy.To form supporting structures, e.g. cell
walls in plants.To be converted to other organic compounds such as
amino acids and fats.For the formation of nucleic acids, e.g.
DNA.To synthesise lubbricants, e.g. mucus which consists of a
carbohydrate anda protein.To produce the nectar in some
flowers.
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BIOLOGY HANDOUTTOPIC: ANIMAL NUTRITION
Teacher in Charge: ARIF ULLAH 4
TYPES OF SUGAR
Sugars are sweet crytalline compounds whch dissolve readily in
water. Two typesof sugars can be distinguished.
i) Simple sugars or monosaccharides:There are numerous simple
sugars. The most common ones are the sugars withsix carbon atoms.
The examples of simple sugars include glucose, fructose
andgalactose. These sugars only differ in structural details and
have the samechemical formula. The structural difference give them
their different chemical andbiological properties.
Glucose is found in nearly all animals. Fructose is found in
plants but uncommon inanimals. Whereas galactose, a component of
milk sugar or lactose, is mainly foundin mammals and rare in other
organisms.
ii) Complex sugars or disaccharides:These are the carbohydrates
in which two molecules of simple sugars condensetogether. They have
a more complex structure than monosaccharides. Examplesinclude
sucrose, lactose and maltose- disaccharides have a general formula
ofC12H22O11.
Sucrose occurs in sugarcane stems, sweet fruits and certain
storage roots. Itconsists of a glucose and fructose molecule
combined together. It is not found inmammals.
Lactose is found in milk of all mammals. It is formed from
glucose and galactosecombined together.
Maltose is found in malted cereals and sprouting grains. It is
formed from partialdigestion of starch and is a combination of two
glucose molecules.
It is to be noticed here that the formation of one molecule of a
complexsugar requires two molecules of simple sugar molecules. It
results in a loss of awater molecule and such a reaction is known
as a condensation reaction.
Therefore, condensation is a chemical reaction whereby two
simple molecules arejoined together to form a larger molecule with
the removal of one molecule ofwater.
Whereas its reverse is hydrolysis reaction in which a water
molecule is added on tosplit up a complex molecule into its
component units is known as hydrolysis or ahydrolytic reaction.
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BIOLOGY HANDOUTTOPIC: ANIMAL NUTRITION
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iii)Polysaccharides:A polysaccharide is made up of many
monosaccharide molecules joined together.The process of condensing
many similar molecules to form a large molecule iscalled
polymerization. Starch, cellulose and glycogen are
polysaccharidesformed from the condensation of the glucose
molecules.
Starch is one of the most important sources of carbohydrates in
food.Starch is not formed or stored by animals.Glycogen is another
polysaccharide which is also known as animal starch.It is a storage
form of carbohydrate in animals and also in fungi. In mammals, it
isstored mainly in the liver and muscles. It is formed when
numerous glucosemolecules condense to form highly branched chains
of glucose molecules.
Glycogen and starch are useful as storage materials because:
they are insoluble in water, so they do not change the osmotic
pressure in cells.they are large molecules and therefore unable to
diffuse through the cellmembranes.they can easily be hydrolysed to
glucose when needed.their molecules have compact shapes so they
occupy less space than thatoccupied by all their constituent
glucose molecules.
Cellulose is the carbohydrate which forms the greatest part of
the cell walls ofanimals. It is inert and very few organisms can
digest it. Man cannot digest it, butit forms the bulk of undigested
matter. This fibre is important to the properfunctioning of the
large intestine.
b)FATS or LIPIDS: (CHO)
Fats are organic compounds made up of the elements carbon,
hydrogen andoxygen; but, unlike carbohydrate, they contain much
less oxygen in proportion tohydrogen.
Fats can be further split into simpler compounds by the process
of hydrolysis. Forexample, when tristearin (beef fat) is hydrolysed
by lipase, it breaks into glyceroland stearic acid.
There is no difference between oils and fats except their state.
Fats are solid andoils are liquids at room temperature. A fat is
said to be saturated when the fattyacids cannot take any more
hydogen whereas in an unsaturated fat, the fatty acidcan take one
or more pairs of hydrogen atoms. Saturated fatty acid chains
arestraight whereas unsaturated fatty acid chains bend at the
places where hydrogencan be taken in.
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BIOLOGY HANDOUTTOPIC: ANIMAL NUTRITION
Teacher in Charge: ARIF ULLAH 6
FUNCTIONS OF FATS:FATS SERVE:
As an efficient source and storage of energy.As an insulating
material (abundant beneath the layers of skin) to preventexcessive
heat loss.As a solvent for fat-soluble vitamins and many other
vital substances, includingsex and related hormones.As a means to
restrict water loss from the surface of the skin. The oily
layerformed on the surface of the skin by the sebaceous skins
constitutes of fats.
Food that are rich in fat include: butter, cheese, fatty meat,
olives, nuts, oils andmany leguminous plants. Normally, humans and
other mammals can manufacturetheir own fat requirements, thus fats
are not essential in their diet. Use of fatsshould be less as
possible and we should try to refrain from saturated fats
(fatsfound in bodies of animals) and use unsaturated fats
(vegetable fats) as much aspossible as they are less risky to cause
heart related diseases.
c)PROTEINS (CHONS)
Proteins are very complex organic substances containing carbon,
hydrogen,oxygen and nitrogen. Sulphur and phosphorus are also often
present.
Proteins are always present in protoplasm. Their molecules are
the largest andmost complex of all the food substances. Every
protein molecule is built up fromsimpler compounds known as amino
acids— the basic units of proteins.
There are 22 naturally occurring amino acids in plant and animal
proteins. Theseamino acids link up with another to form long
chains. When two amino acids linkup, there is a removal of one
molecule of water which means that proteins areformed by
condensation reactions. The bond formed between any two aminoacids
is very strong and is known as a peptide bond. If 3 or more amino
acidsare linked up with peptide bonds, a polypeptide bond is
formed. An average aminoacid chain contains about 500 units.
One or more of such chains together form protein molecules. The
amino acidchains in a protein molecule are not straight. They are
often coiled to give proteinsa special 3D shape. The coils are held
in place by weak cross_links (hydrogenbonds) which are easily
broken by heat, acids and alkalis. The breaking of thesecross-links
causes the denaturation of protein. Now it is easily understood
thatwhy enzymes, which are made of proteins have a special active
site (3D structure)and why they are denatured over high
temperatures (weak hydrogen bonds).
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BIOLOGY HANDOUTTOPIC: ANIMAL NUTRITION
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PROTEIN DEFICIENCY:The deficiency of proteins in the diet of the
children may lead to a disease knownas kwashiorkor. Such children
have swollen abdomens and their skins crack andbecome scaly. Doctor
suggests around 50-100 grams of daily intake of protein foran
average adult.
FUNCTIONS OF PROTEINS: Proteins are:
Essential for synthesis of protoplasm.For growth and repair of
worn out body cells.Used for synthesis of enzymes and hormones.Used
for formation of antibodies to combat diseases.A source of
energy.
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BIOLOGY HANDOUTTOPIC: ANIMAL NUTRITION
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d) WATER (H2O)
Water is extremely important to survive because it is a major
constituent ofprotoplasm. A person can stay longer without food
than without water.
FUNCTIONS OF WATER:Water serves as:
A medium in which various chemical reactions occur.A
transporting agent for:Digested food substances, Excretory products
andHormonesAn essential component of:Lubricant found in joints, The
digestive juices.and Blood
Moreover, it has the following functions:Needed for hydrolytic
reactions (digestion).It also helps to regulate the body
temperature.
e) Roughage/Dietary Fiber/Green Vegetables:It helps in the
movement of food during peristalsis.It adds bulk to the food.
f) VITAMINS
Vitamins are a group of chemically unrelated organic compounds
required in thediet in very minute amounts. Most of the vitamins
are obtained from the plantsbut some of them are also obtained from
the tissues of other animals or areproduced by microorganisms
living in the gut.
Vitamins are not built in a definite pattern like carbohydrates,
proteins and fats.They neither provide energy nor are they
body-building food. However they arestill required for normal
health and development.
Vitamins can be either fat soluble or water soluble. Fat-soluble
vitamins aresoluble in fats and can be stored in the body fats,
whereas water-soluble vitaminscannot be stored in the body and have
to be therefore supplied in the daily diet.
Vitamin deficiency or excessive usage can both lead to serious
diseases andtherefore great consideration should be used to consume
appropriate proportionsof vitamins in the daily dietAr
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BIOLOGY HANDOUTTOPIC: ANIMAL NUTRITION
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SOME IMPORTANT VITAMINS
VITAMIN D (FAT-SOLUBLE):Vitamin D is found in fish-liver oils,
egg yolk and margarine. However, ultravioletrays in sunlight can
convert a natural substance (ergosterol) in the skin to vitaminD.
it is relatively resistant to heat and oxidation. Vitamin D
promotes absorption ofcalcium and phosphorus from the intestines.
It also enables the body to use thesecompounds in the formation of
teeth and bones. Deficiency can lead to a diseaseknown as Rickets
in growing children. Diseased children have poor teeth andbone
formation. The soft bones bend under body weight. In adults bones
soften,which is also known as osteomalacia. Excess consumption may
result indemineralization of bones and calcification in many soft
tissues.
VITAMIN C (WATER-SOLUBLE):It is found abundantly in fresh citrus
fruits (oranges, lemons) along with otherfruits (papaya, bananas).
It is also found in fresh green vegetables. It is easilydestroyed
by heat (cooking and canning). It is needed for the formation
ofintercellular substances. Such substances are found in between
the cells and theyhold the cells together. They are also necessary
for maintaining healthy epithelialtissues. Lack of it leads to
scurvy- a disease characterized by swollen, bleedinggums and
loosening of the teeth, internal bleeding and painful swollen
joints.Excess is excreted by the body.
VITAMIN A:This is needed for the formation of a light sensitive
pigment in the retina and formaintaining healthy epithelial
tissues. Rich sources include dairy products andgreen leafy
vegetables. Night Blindness is caused due to its lacking.
VITAMIN B COMPLEX:Several of it are important coenzymes in
cellular respiration. Beri-beri, pellagraand anaemia are diseases
caused by a lack of certain B vitamins. Yeast, liver andbrain are
rich sources.
g) MINERALS:
Mineral elements are in organic salts which do not provide
energy but arenecessary for body functions.
We obtain minerals from other animals or plants. Some minerals
are required inlarge amounts whereas others are required I minute
amounts. The minerals whichare required in large amounts include
calcium, phosphorus, sodium, chlorine,potassium and iron.
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BIOLOGY HANDOUTTOPIC: ANIMAL NUTRITION
Teacher in Charge: ARIF ULLAH 10
SUMMARY of Important VITAMINS
SUMMARY of Important MINERALS
Nutrition is the process of providing or obtaining the food
necessary for healthand growth.Primary: Secondary:1.Carbohydrates.
1. Minerals.2. Fats. 2. Vitamins.3. Proteins. 3. Roughage/Dietary
fiber.4. Water.
Primary food substancesare needed for living.Secondary
FoodSubstances are needed tostay healthy.
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BIOLOGY HANDOUTTOPIC: ANIMAL NUTRITION
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A Balanced Diet contains all the necessary nutrients like
carbohydrates, proteins,fats, minerals, vitamins, water and
roughage needed for healthy growth, in theright proportion.
Dietary energy requirement is related to:Activity: the more
active a person is the greater the amount of energy needed.Age:
teenagers and young adults need more energy per kilogram body mass
thanyoung children and old people.Sex: for the same body size and
age, men use more energy than women.
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BIOLOGY HANDOUTTOPIC: ANIMAL NUTRITION
Teacher in Charge: ARIF ULLAH 12
The Human Digestive System:
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BIOLOGY HANDOUTTOPIC: ANIMAL NUTRITION
Teacher in Charge: ARIF ULLAH 13
The Alimentary Canal/ Gut.The alimentary canal is a long
muscular tube through which food is moved alongin our body. It
starts with the mouth and ends with the anus.Main regions of the
alimentary canal and associated organs, and their functions:
Mouth: Entrance of the buccal cavity. Food enters the buccal
cavity and isswallowed or ingested.
Teeth: Chewing, i.e. cutting up food into small pieces.Tongue:
Mixes food with saliva, shapes food into a bolus and helps
inswallowing it.Salivary gland: Produces saliva which consists of
water, mucus and anenzyme (salivary amylase) to start digestion of
cooked starch.
Oesophagus: Narrow muscular tube stretching from mouth to
stomach. Cellslining its walls secrete mucus.
Muscles in oesophagal wall: Send food from mouth to stomach
byperistalsis-the wave-like rhythmic contractions of the alimentary
canalwhich pushes food along it.
Stomach: Bag-like, muscular structure with sphincters at its
entrance and exit toopen and close it.
Gastric glands in the stomach walls: Produces gastric juice made
up ofwater, mucus, hydrochloric acid and enzymes. The enzymes bring
aboutchemical digestion of proteins.Muscles in stomach walls: Cause
churning action, breaking down foodmechanically into small pieces
and mixing it with gastric juice for betterchemical digestion. The
muscles also cause peristalsis to push food intothe small
intestine.
Liver: Produces bile which contains water, alkali and bile
salts. Bile salts help infat digestion by breaking up fat into tiny
droplets (emulsification).
Gall bladder: Stores bile temporarily before sending it to the
duodenum (smallintestine).
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BIOLOGY HANDOUTTOPIC: ANIMAL NUTRITION
Teacher in Charge: ARIF ULLAH 14
Pancreas: Produces pancreatic juice which is sent to the
duodenum. This juicecontains water, alkali, and enzymes. The
enzymes digest carbohydrates, fats andproteins.
Small intestine: Six-meter long narrow, coiled tube made up of
duodenum,jejunum and ileum.
Duodenum: U-shaped tube. Receives bile and pancreatic juice to
digestnutrients in the chime from the stomach.Ileum: Long coiled
tube. Contains intestinal glands in its walls. Walls arefolded and
have villi.Intestinal glands: Produces intestinal juice which
contains water, mucus,alkali and enzymes. These enzymes complete
digestion ofcarbohydrates, fats and proteins.Villi: Have adaptive
features that facilitate absorption of digested foodinto blood.
Large intestine: A 1.5 meter long, wide tube that is made up of
the caecum andthe blindly ending appendix, colon and rectum. It
completes absorption of waterand minerals, resulting in faeces
formation.
Colon: Shaped like an inverted “U”. Absorption of water and
mineralsfrom the indigestible food occurs here.Rectum: A short
muscular tube. Stores faeces temporarily. Faecescontain
indigestible food, germs, mucus and dead cells.Anus: Opening
through which faeces are expelled (Egestion).
Steps of Nutrition:1. Ingestion: Food is taken into the
alimentary canal.2. Digestion: Large insoluble molecules of food
are broken down to small
molecules.3. Absorption: Transport of food into the blood
through the intestinal walls.4. Assimilation: Conversion of
absorbed food by cells in body into new
protoplasm to bring about growth.5. Egestion: Food which could
not be digested or absorbed is removed from
the body
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BIOLOGY HANDOUTTOPIC: ANIMAL NUTRITION
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Mechanical digestion: This is the cutting, tearing and grinding
of solidfood into small pieces by chewing and churning. Food is
broken down into smallpieces thus providing a large surface area
which is essential for effective chemicaldigestion.
Chemical digestion: This is the process which changes complex
insolublefood into simple molecules that can diffuse across cell
membranes into the blood,for transporting to different parts of our
body by the action of enzymes.
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BIOLOGY HANDOUTTOPIC: ANIMAL NUTRITION
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Peristalsis: The rhythmic contraction and relaxation of the
longitudinal andcircular muscles in order to move food along the
gut.The two layers of smooth muscles cause rhythmic, wave-like
contractions of thewalls of the gut. Such movements, known as
peristalsis, moves food along the gut.The two sets of muscles work
in such a way that when one contracts, the otherrelaxes. When the
circular muscles contracts, the longitudinal muscle relaxes.
Antagonistic pairs: push and pull, opposite effect.The muscles
which act oppositely to one anotheri.e. if one contracts and the
other relaxes and vice versa.E.g.Animal Nutrition:1) Circular and
longitudinal muscles in the gut.Support and movement:2) Biceps and
triceps in the arms.
Co-ordination:3) Circular and radial muscles in the Iris.4)
Suspensory and ciliary muscles in the lens.
Transport in Animals:5) Internal and external inytercostal
muscles in the rib-cage.
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BIOLOGY HANDOUTTOPIC: ANIMAL NUTRITION
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Summary of Digestion in Humans:
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BIOLOGY HANDOUTTOPIC: ANIMAL NUTRITION
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Structure and functions of a Villus:
Features How it works
1. It is very long, about 5m in an adult. This gives plenty of
time for digestion to becompleted, and for digested food to
beabsorbed as it passes through.
2. It has villi. Each Villus is covered withcells which have
smaller projectionson them, called microvillus.
This gives the inner surface of the smallintestine a very large
surface area; the fasterfood can be absorbed.
3. Villi contain blood capillaries. Digested food passes into
the blood, to betaken to the liver and then around the body.
4. Villi contain lacteals, which are part ofthe lymphatic
system.
Fats are absorbed into the lacteals.
5. Villi have walls only one cell thick. The digested food can
easily cross the wall toreach the blood capillaries and
lacteals.
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BIOLOGY HANDOUTTOPIC: ANIMAL NUTRITION
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Functions of liver:1. Storage of food substances.2. Control of
blood – Glucose level.3. Detoxification – Conversion of toxic,
harmful substances before
excretion.4. Protein synthesis.5. Heat production – Due to
metabolic process – Catabolic and anabolic
process.6. Storage of iron – worn out RBCs are broken down into
bile slats and
Hemoglobin. Hemoglobin is stored as Fe/ Iron.7. Deanimation –
Excess Amino acids are broken down into ammonia
and glucose. Ammonia is converted into urea and excreted
alongwith urine and glucose is stored as glycogen or used
duringrespiration.
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BIOLOGY HANDOUTTOPIC: ANIMAL NUTRITION
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Difference between Excretion and Egestion:Egestion Excretion
It is the removal of undigested foodsubstances.
It is the removal of metabolic wasteproducts.
It takes place through anus. It takes place through lungs
kidneysand skin.
Example: Faeces. Example: Sweat, CO2, Urine.
ORT:Oral rehydration therapy (ORT) is a simple treatment for
dehydration associated
with diarrhea, particularly gastroenteritis or
gastroenteropathy, such as thatcaused by cholera or rotavirus. ORT
consists of a solution of salts and sugars thatis taken by mouth.
It is used around the world, but is most important in thedeveloping
world, where it saves millions of children a year from death due
todiarrhea, the second leading cause of death (after pneumonia) in
children underfive.
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Food tests:Test for starch (iodine test):Add few drops of Iodine
solution (KI2) to the food sample.If the color changes to
blue/black, starch is present.If the color remains brown/ yellow,
starch is absent.
Test for glucose (reducing sugar) – Benedict’s test:Add equal
amount of Benedict’s solution to the food sample (crush the
foodsample and add water if the food sample is solid). Heat the
solution in a waterbath.If red precipitate is seen, glucose is
present.If the color remains blue, glucose is absent.
Test for proteins (Buiret Test):Add equal amount Buiret 1 and 2
solution to the food sample.If the color remains Blue, Protein is
absent.If color changes to purple, protein is present.
Test for fats:a) Emulsion/ Ethanol Test
Add the food sample to Alcohol/ Ethanolthen add water.If color
is milky, fat is present.If color changes to clear, fat is
absent.
b) Grease- Spot testRub the food sample on a white paper.If a
translucent/ semi-transparent spot is formed, fat is present.If
clear, no fat is present.
Arif
Ullah
- IT
HS -
0181
7721
521
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INTERNATIONAL TURKISH HOPE SCHOOL-CHITTAGONG BRANCH2017-2018
BIOLOGY HANDOUTTOPIC: ANIMAL NUTRITION
Teacher in Charge: ARIF ULLAH 23
Arif
Ullah
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HS -
0181
7721
521
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INTERNATIONAL TURKISH HOPE SCHOOL-CHITTAGONG BRANCH2017-2018
BIOLOGY HANDOUTTOPIC: ANIMAL NUTRITION
Teacher in Charge: ARIF ULLAH 24
Arif
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INTERNATIONAL TURKISH HOPE SCHOOL-CHITTAGONG BRANCH2017-2018
BIOLOGY HANDOUTTOPIC: ANIMAL NUTRITION
Teacher in Charge: ARIF ULLAH 25
Calorimeter:
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INTERNATIONAL TURKISH HOPE SCHOOL-CHITTAGONG BRANCH2017-2018
BIOLOGY HANDOUTTOPIC: ANIMAL NUTRITION
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Teeth:Their job is to cut, tear and grind food. To give it more
surface area for faster Digestion,they do mechanical
digestion.Types of mammalian teeth:• Incisors: There are 4 in front
of each jaw.
They act like a blade to cut food(eg. To cut a bite of a
sandwich)They have a (chisel-like surface).
• Canines: There are two in each jaw.They are very pointed, in
humansThey are used for the same purpose as incisors.However in
carnivores they are longer and sharper and used to kill the
prey.
• Premolars: There are 4 on the sides of each jawThey are used
to cut and grind food
• Molars: There are 6 at the back of each jaw, 2 of them are
wisdom Teeth.They have the same use as Premolars.
Note: Remember that we have two jaws, so 4 incisors in each jaw
means that wehave a total of 8 incisors in our mouth. We have 16
teeth in each jaw, 32 in thewhole mouth.
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INTERNATIONAL TURKISH HOPE SCHOOL-CHITTAGONG BRANCH2017-2018
BIOLOGY HANDOUTTOPIC: ANIMAL NUTRITION
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Parts of the tooth:
Enamel: made of calcium salts, it is very strong.Dentine: it is
covered by the enamel and surrounds the pulp cavity.The pulp
cavity: it contains the nerves and blood vessels.The part of the
tooth above the gum is called the crown, the part buried in the
jawbone iscalled the root. The enamel covers the crown, the root is
covered by cement. And thetooth is held in place by fibres.
Tooth Decay: when we eat, some food particles stay in our mouth.
Bacteria that lives inour mouth feed on these food particles, they
respire anaerobically producing lactic acid.Like any acid, lactic
acid reacts with the enamel and dissolves it away reaching the
dentine,here we feel the toothache.
Decay is a gradual process that follows a well-recognized
pattern if it is left untreated:1. The acid erodes the tooth enamel
just under the surface in a small area that is hard to
detect. A small white spot may be visible. At this stage,
reversing the damage is stillpossible.
2. The damage continues through the enamel until it reaches the
softer dentine. At thisstage it can be said that a true cavity has
formed. It can then ‘mushroom’ out ratherquickly, destroying the
dentine. A lot of the structure can rot away without one knowingas
the hard enamel can stay intact. Once decay reaches the dentin, the
damage done ispermanent and will only progress.
3. The decay will eventually reach the dental pulp where the
nerve lies. Root canal or toothextraction will be needed.
Arif
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INTERNATIONAL TURKISH HOPE SCHOOL-CHITTAGONG BRANCH2017-2018
BIOLOGY HANDOUTTOPIC: ANIMAL NUTRITION
Teacher in Charge: ARIF ULLAH 28
Methods Of preventing Tooth Decay:• Reduce sugar intake to
prevent bacteria respiring• Brush teeth to remove the plaque layer
of bacteria and saliva on our teeth and nuetralise
mouth• Use toothpaste or water containing fluoride because it is
absorbed by the teeth and
helps stopping the attack by acid• Pay regular visits to the
dentist.
Advantages• Suitable amounts prevent tooth decay
• It is a cheaper method of teeth caringDisadvantages
• Too much causes teeth molting, illness and abdominal pain• It
is expensive
Arif
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0181
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INTERNATIONAL TURKISH HOPE SCHOOL-CHITTAGONG BRANCH2017-2018
BIOLOGY HANDOUTTOPIC: ANIMAL NUTRITION
Teacher in Charge: ARIF ULLAH 29
Arif
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HS -
0181
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INTERNATIONAL TURKISH HOPE SCHOOL-CHITTAGONG BRANCH2017-2018
BIOLOGY HANDOUTTOPIC: ANIMAL NUTRITION
Teacher in Charge: ARIF ULLAH 30
Arif
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HS -
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